1. Field of the Invention
This invention relates to a new and improved lamp for use under submerged conditions and under circumstances where the bulb base and leads are exposed to water and other environments which are detrimental to conventional lamps. More particularly, the invention relates to a new and improved lamp assembly, including a bulb and base, which is coated with a silicone composition to make the entire assembly waterproof. The assembly may then be inserted in any one of several conventional brackets and mounted as desired. In one embodiment of the invention, the bulb, base assembly and leads are coated with a thin film of silicone material, which film provides a protective coating over the bulb and lead connections to minimize the effect of thermal and impact shock as well as corrosion resistance when the light is dropped on a hard surface or immersed in water, or otherwise exposed to corrosive environments. The film forms a sealed coating which prevents moisture from entering the lamp assembly, including the bulb and base units.
2. Description of the Prior Art
Heretofore, various attempts have been made to provide a lamp assembly having a protective coating to protect the assembly against the effects of water and other harsh environments which tend to corrode the assembly, and also against thermal and impact shock which causes the bulb to break. Such lamp assemblies have a wide variety of uses, such as illumination of instruments in airplanes, boats and the like, and use in all vehicles, including automobiles, tractor trailers, trucks, boat trailers, automobile trailers and similar vehicles, as back up lights, tail lights, clearance and side marker lights. One factor which frequently causes difficulty in the use of miniature lamp assemblies is the high operating temperature of the lamps due to the small radiation surfaces of the bulbs used. Accordingly, when such lamps are used in vehicle trailers and particularly, boat trailers which must frequently be submerged to load and unload boats, the thermal shock caused by the hot lamp touching the cool water frequently results in breakage of the bulb. Another problem inherent in the use of both large and small lamps is breakage when the lamp is dropped on a hard surface such as concrete. Yet another problem frequently realized as a result of exposure of the lamp assembly to harsh environments such as salt water and areas of high humidity, is the problem of corrosion at the point where the leads join the lamp busses or filament bases. This problem is frequently intensified by moisture seeping into the lamp base area from the annulus between the connector wire and its insulating jacket as a result of breaks in the insulation between the lamp base and the electrical source. Accordingly, when bulbs are changed in the lamp and bracket assembly, corrosion frequently prevents good electrical contact between the base or busses of the lamp and the leads, thereby frequently inhibiting proper operation of the lamp.
Yet another problem inherent in conventional lamps is the tendency for corrosion to occur at the point where the filament busses touch the wire leads in the metal mounting bracket itself.
Accordingly, an object of this invention is to provide an improved lamp which is resistant to thermal and impact shock, which is corrosion resistant, and which is adapted to fit into conventional mounting brackets.
Another object of this invention is to provide a new and improved lamp which is coated with a silicone composition to impart corrosion, impact shock, and thermal shock resistance to the lamp assembly, and to prevent moisture from entering any part of the lamp assembly.
A still further object of the invention is to provide a miniature lamp assembly which is coated with a thin layer of silicone composition to prevent the bulb from breaking when the assembly is exposed to rapidly changing temperatures, corrosive environmental conditions and dropped on hard surfaces.
Yet another object of the invention is to provide a new and improved base and bulb light assembly to which base leads are soldered or otherwise appropriately connected, and an appropriate silicone composition coating is applied to the bulb base and leads to provide a sealed unit and impart corrosion resistance, thermal shock resistance, and impact shock resistance to the assembly.
Another object of the invention is to provide a method of encapsulating small lamps and bulbs and the lead connections thereto in a sealed unit with a silicone composition to provide thermal and impact shock resistance and corrosion resistance to the lamps and bulbs, which sealed unit is capable of being removably inserted into a conventional mounting bracket.
A still further object of the invention is to provide a new and improved lamp assembly and procedure for coating the assembly with a silicone composition by use of a rubber boot designed to fit on the leads and accumulate the silicone composition in the appropriate position over the lead connections in order to insure adequate coating of the connections and to provide a suitable means for holding the lamp assembly in place inside a conventional bracket without the necessity of springs or other means for achieving good contact between the vehicle lead wires and the lamp assembly.
Yet another object of the invention is to provide as improved sealed encapsulated lamp which is not subject to corrosion from moisture seeping into the lamp base from breaks in the lead wire insulation and which removably fits inside substantially any conventional holding bracket.